The Frankish World
The one western kingdom that did claim to have replaced the empire, and the thing it turned into. A Frankish king was crowned emperor in Rome in 800 and the title outlived his dynasty, his kingdom and the division of his inheritance by a thousand years.
The line below is a time axis. Position on it is date, so concurrency is visible: concurrent polities sit side by side rather than in sequence.
7 sourced edges run between this region and another, to Roman Empire, Kingdom of Sicily, Republic of Florence, Lombard Kingdom, Duchy of Normandy and Avar Khaganate. Those are not drawn on this line — a thread that crossed regions would assert a sequence nobody cited — but they are on each polity’s own page.